In various environments, the oxygen content in ambient air is altered just enough to have a perceptible effect on a human. For example, at higher altitudes on land, performance levels during physical exertion or even when a body is at rest may be impacted by a drop in oxygen concentration in ambient air of even less than 1 percent. Further, in enclosed spaces where air is conditioned and circulated, including, buses, trains, buildings, etc., minor fluctuations in oxygen content can occur. In addition, during air travel, cabin pressurization and ambient air circulation is optimized to deliver oxygen content to passengers approaching or substantially approximating oxygen levels on land. In most instances, such minor variations in air component composition and, in particular, oxygen concentration are not noticed by, or otherwise do not adversely impact, air passengers. Some passengers, however, have experienced so-called “jet lag”, typically on longer flights that may be exacerbated in individuals having a physiological sensitivity to oxygen concentration changes in their environment.